Autism is a disabling neurological disorder that affects thousands of Americans and encompasses a number of subtypes. There are various putative causes of autism, but few ameliorative treatments. Autism may be present at birth, or it may develop at a later age usually early in life, for example, at ages two or three.
Autism is defined behaviorally because there are no definitive biological markers of the disorder. Behavioral symptoms of autism include abnormal development of social skills (e.g., withdrawal, lack of interest in peers, etc.), sensorimotor deficits (e.g., inconsistent responses to stimuli), and limitations in the use of interactive language including both speech and nonverbal communication. Additional impairments often seen in autism include echolalia, poor symbolic thinking, a lack of imagination, self stimulation, and self injury behaviors. Disorders that often accompany autism include attention disorders, seizure disorders, Tourette's syndrome, tuberous sclerosis, mental retardation, mood disorders, depression, and other psychiatric disorders.
A limited number of treatments for autism have been developed. However, most of the treatments address the symptoms of the disease instead of the causes. For example, therapies ranging from psychoanalysis to psychopharmacology have been employed in the treatment of autism. Although some clinical symptoms may be lessened by these treatments, substantial improvement has been demonstrated in very few autistic patients. Only a small percentage of autistic persons are able to function as self-sufficient adults.
Various regions in the brain have been shown to demonstrate structural or functional abnormalities in connection with a diagnosis of autism. For example, numerous imaging studies have demonstrated increased brain size and volume in autistic patients, consistent with head circumference and postmortem studies. Studies examining regional variations suggest significant enlargements in the temporal, parietal, and occipital lobes.